These clear 12-volt incandescent bulbs were used in vintage trailer interior light fixtures and some backup lights. Identical to a standard 1156 bulb but with a lower wattage (18 watts instead of 27 watts for an 1156) so less likely to melt plastic lenses or diffusers if in close proximity or where there is limited air flow in the fixture.
A good bulb for porch lights where a slightly dimmer and cooler bulb is desired.
The bottom of the bayonet style base has only 1 contact point. The two bayonets on the sides are directly opposite each other. The technical name for this type of base is BA15S.
Box of 10.